A pie chart visualizes customer spending across four categories—Food, Clothing, Electronics, and Entertainment—using quantitative values. Built with D3.js v7, it renders an SVG slice for each category, sized by its value, with labels positioned at each slice’s centroid. A color scale from `d3.schemeCategory10` and `d3.scaleOrdinal` map categories to fills, while `d3.arc` and `d3.pie` compute the geometry. A separate HTML legend lists each category with its corresponding color and value. The chart uses a fixed 500×500 pixel canvas and is re-rendered by clearing and redrawing the SVG elements.